Metallurgy of Mining and Metallurgical Engineering Machinery, 5, Densification and Microstructure Analysis of Alloys Chen Shiqi, Qu Xuanhui. Huang Boyun. Lei Changming, State Key Laboratory of Powder Metallurgy, Central South University of Technology, Changsha, Hunan 483, found that the use of hot-pressing techniques can be used to prepare fine powders with 5 micron powders. Evenly distributed to the contact material. The material shows a higher thermal stability. At the same time, the changes in the microstructure and the process of desolvation of supersaturated solid solution during the densification process were analyzed, and the contact material was profitable. With, the island's voltage strength is a great breaking capacity and good resistance to welding and interception, widely used in vacuum circuit breaker contact material. However, with the development of high-voltage, large-capacity and small-sized vacuum circuit breakers, the production of contact materials due to the existence of defects such as coarse distribution and uneven distribution has not satisfied the requirements for use. In recent years, the results of the old six-day development have been rampant, and fine-grained alloys have shown great progress before proceeding. However, there is a large difference between the component defects, and almost no mutual dissolution in the solid state, so that the conventional melting method and the powder metallurgy method can not produce uniform grain microstructure. Contact material. The mechanical alloying method is suitable for preparing fine-grained or even nano-crystalline materials, and achieves atomic level mixing between constituent elements, which is favorable for mass production. In this paper, alloy powders were prepared by mechanical alloying and the densification process and microstructure of the powders were studied. A new method for the preparation of fine-grained 1 gold was explored. The new experimental method for powder was used as a raw material. The powder was loaded on a self-made agitated ball mill at a ratio of 1 to 24 for mechanical gold galvanization. The powder coating sample was subjected to ray diffraction. Analysis and appearance observation. Then, the above powders were subjected to hot-press densification. The high-strength graphite molds were used for the hot stamping molds. The pressures were 60 shank temperatures, 750, 850, 950, and 10005 respectively. The thermocouples were used for temperature measurement, and the temperature control accuracy was ±5. The hot pressed sample is then subjected to density testing and tissue observation. 2 Test results 21 Mechanical alloying, 50 powder analysis appearance, compared with the powder before ball milling, ball milling to make the powder refinement occurred in the absolute part of the powder refinement to about (1) Lishan powder shape is multi-curved, children The surface of the powder was cracked, and some of the small powders adhered. After the powder was introduced into the composition and analyzed, it was found that homogenization between 0 and 0 was observed in the powder, which broadened the peaks. This is due to grain refinement. After analysis, the grain size is below 10,1; at the same time, the diffraction peak intensity of 1 is obviously reduced. 1 Fund project The original high-tech new material project of the High-tech New Materials Corporation, the hot-pressing temperature t 1 after hot pressing, 1000.2 heat treatment; 2 hot pressing Weak, Cr peaks are enhanced, and Cu is dissolved in Cr crystals to form a forced solid solution. 22 Mechanical alloying, 50, 50 powder densification study temperature changes. From 3, it can be seen that under the experimentally selected hot-pressing pressure, the density is significantly improved with temperature derivation, at 750, hot pressing. 1. The relative density of the sample is 56. In 1950, the relative density can reach 95.7, and at 1 o'clock, the density can be improved to 97. This result shows that the hot pressing temperature is! Key factors affecting the densification of alloys. 3 lists the effect of hot pressing temperature on alloy density. By 3, the heat treatment of the low-temperature treatment sample has an improved sintering effect, the density has a greater increase, and for the same temperature hot-pressed sample, the density is almost constant, and the subsequent heat treatment on the relatively high density of the alloy progresses densely. It does not have a significant effect. 23 It can be seen from the analysis of the microstructure of 5,5 alloys that the metallurgical structure consists of 1 and phases, in which the dark phase is white. In 850, hot pressing, because its relative density is only 74, its organization is clear! 1 The heart of the original human powder sumer measures the pores, and the black part between hunger and powder is pores, while the interior of the original powder is EMWdUzPjALujjWjcWMB. In the 950 hot pressed metallurgical structure, the original and powder form can still be clearly identified. However, it has been difficult to observe the pores. A large number of 1 precipitates occurred at the boundary of the original Heren Powder43, and some parts of the powder were analyzed. 00, when hot pressed, the tissue can still distinguish the original tender powder morphology, but it is not very obvious, and the precipitation is not only carried out on the side of the original powder. In addition, the person inside the body of the powder is exposed. By comparison, it can be found that the 100 hot press has a longer fire than the hot pressed grains in the Tantalum Plant, but it does not seem that the fine grain structure is maintained in both pieces, and the 00c hot press has better organization uniformity. 1 After the heat treatment, it can be seen that during the subsequent treatment, aggregates grow at the boundary of the original powder, and at the same time, the inside of the powder into the powder is also precipitated and precipitated. As the aggregate grows up, the grain structure also has a long fire. However, it is not very clear. The above result shows that the supersaturated solid solution forming 1 in the mechanical alloying process is precipitated during hot pressing. However, in the hot press, the precipitation process is not complete, and will continue to occur during the subsequent heat treatment, so that the shedding of 1 is more complete. 3 Discussion Department, 1 The alloy is actually a simple alloy and a pseudoalloy. The above results show that the continuous collision of the component elements in the mechanical alloying process causes the powders to be refined and the components to be homogenized during the fracture process. After 24 mechanical alloying, sufficient homogenization and crystal grains have been achieved between the 1 components. The ultra-thinning; on the other hand driven by the mechanical force, so that insoluble, forming a mandatory solid solution between the component part into the body to form a supersaturated solid solution. This solid solution is a thermodynamically non-equilibrium state and has a equilibrated state, ie, a phase transition. In this experiment, a simple and easy hot-pressing process was used to densify the powder. As a result, the densification process was mainly related to the temperature. The addition of temperature facilitates the displacement and deformation of the powder and facilitates the densification process. In addition, the hot pressing process occurs. It is known that the precipitation site tends to the original powder boundary at a low temperature, and the powder at high temperatures. A large amount of internal precipitation increased, which implies that the increase in densification of each instrument at higher temperature hot presses is also beneficial to the improvement of demixing and homogenization of the structure. The positive result of Yang 41 is also clear. This cannot be done completely, and subsequent heat treatment will facilitate the completion of this process. With the precipitation, the grain grows obviously in the hot-press densification. The nano-scale of the powder state grows up to the micron level, but in the hot-pressing process of 95,1, the grain does not improve significantly. The bright grains have a high thermal stability, which is a feature that makes it possible to use a higher temperature for densification. 4 Conclusions Mechanical alloying can produce homogeneous grain ultrafine mechanical alloying. The densification of the powder is mainly related to 1 degree. In the 1000, hot press process, the relative density of the sample can reach 97.1. The supersaturated solid solution formed during the mechanical alloying process undergoes desolvation during the thermal densification process, and the increase in temperature promotes the 1. alloy prepared in the 4 tests of the desolvation process. Product granules 1. Fine weaving, uniform distribution, high thermal stability. 1 Wang Yaping. Wait. High voltage electrical appliances, 1997, 234 2 Wang Yongxing, Zou Heyan. Rare Metals and Cemented Carbides, 19 Sun 3 Suppl 360 Hex Bolt Sleeve Anchor Hebei Qianmu Fastener Manufacturing Co., Ltd , https://www.qmjgjfasteners.com